Carbohydrates

Question 1

List the simple carbohydrates and describe their dietary importance

Answer 1

Monosaccharides:

Disaccharides:

Question 2

List the complex carbohydrates and describe their dietary importance

Answer 2

Oligosaccharides:

Polysaccharides:

Question 3

Explain why glucose is an essential nutrient

Answer 3

Glucose is used for glycogenesis, lipogenesis,synthesis of non-essential amino acids and it’s oxidized for energy production.

Question 4

Describe the digestion of carbohydrates

Answer 4

Monosaccharides: no digestion required

Starches:
Small intestine - major, mouth and stomach - minor
Alpha-amylase
- secreted by salivary glands and pancreas
- hydrolyzes alpha-1,4 linkages from glucose, maltose and isomaltose

Dissacharidases

• active in microvilli of enterocytes
• sucrase splits sucrose
• lactase splits lactose
• maltase splits maltose
• isomaltase splits isomaltose (alpha-1,6 linkage)

Question 5

Describe the absorption and transport of carbohydrates

Answer 5

Glucose and galactose:
Into blood: facilitated diffusion (GLUT2)
Into cell: active transport (SGLT1) and facilitated diffusion (GLUT4)

Fructose:
Into blood: facilitated diffusion (GLUT2)
Into cell: facilitated diffusion (GLUT5)

Question 6

Describe the storage of carbohydrates

Answer 6

Glycogen

Question 7

Describe the metabolism of carbohydrates

Answer 7

Glycogenesis - conversion of glucose into glycogen for quick storage
Glycogenolysis - breakdown of glycogen to glucose during times of high energy demand
Glycolysis - break down of glucose to pyruvate
Gluconeogenesis - reverse of glycolytic pathway, synthesis of glucose from non-CHO precursor
Trcarboxilic acid (TCA) cycle - accounts for 90% of energy released from food, ATP produced from complete glucose oxidation,

Question 8

List some food sources of carbohydrates

Answer 8

Grains, tubers, legumes, some fruits & veggies

All carbohydrates are sourced from the sun - photosynthesis

Question 9

Discuss carbohydrates and dental health

Answer 9

Streptococcus mutans produce acids from sugars (glucose, fructose, lactose, sucrose & maltose).
Acids cause tooth decay.

Sucrose can be converted into polysaccharides, called dextrans, which stick to the tooth and form plaque that attracts sugars

Question 10

Define glycemic index and glycemic load

Answer 10

Glycemic index: increase in blood glucose during a two hour period after consumption of a certain amount of CHO compared with equal CHO from reference food.

Glycemic load: GI x g of CHO in one serving of the articular food.

Question 11

D-ribose is a component of what in all living cells?

Answer 11

RNA
DNA
ATP

Question 12

Why are clinical applications of D-ribose?

Answer 12

Heart disease
ATP deficiency in muscle related disease
Sports medicine - extended endurance, improved muscle recovery

Question 13

What are cautions when supplementing D-ribose?

Answer 13

May cause mild hypoglycemic effect

May cause increase in uric acid levels

Question 14

When would one use D-mannose clinically?

Answer 14

E. coli positive UTI

Question 15

What are adverse effects of consuming refined sugars?

Answer 15

They’re empty calories
Dysglycemia & dysinsulinism
Increased cardiovascular disease risk factors
- increased TGs, decreased LDL, increased BP, increased platelet adhesiveness
- decreased immune function
- diarrhea, gas and bloating and other GI symptoms

Question 16

Discuss xylitol, it’s benefits and when it is used

Answer 16

A sugar alcohol - tastes sweet
No caloric intake

Clinical indication

• cavity prevention and treatment
• • streptococcus mutans can’t metabolize it
• • most important during pregnancy and during tooth development